Ohio Spiderwort (Tradescantia ohiensis)

Blue Jewels of the Prairie
By Anita Carpenter

In early June, the delicate, lacy-like yellow flowers of golden Alexander are fading. Meanwhile, three-foot tall, ramrod-straight stems of tall penstemon, each adorned with several 3/4-inch white tubular flowers, begin to assume their prominent role in the prairie. About the same time, and with little fan-fare, blue flowers seem to magically appear to share the spotlight with penstemon.

I rejoice, for spiderwort, one of my favorite flowers, is now revealing its unique beauty to the world and to those who pause to admire. I wonder though, how did these two-foot tall spiderwort plants remain undetected until it was time to bloom? A closer look at this plant may provide an answer.

Common spiderwort or Ohio spiderwort (Tradescantia ohiensis) is a native perennial plant with stiff, narrow, 1/3-inch-wide pointed leaves. In its early growth, spiderwort, with its narrow, pointed leaves, could easily be mistaken for grass and be overlooked. Eventually, each plant sends up a single, mostly straight, smooth, slender, round stem, which may or may not be branched. Again, spiderwort becomes “lost” in the surrounding foliage.

Its unexpected debut in the prairie excites me, and I always pause to admire this unique flower. First to catch my eye are the flower buds that hang down in a tightly packed terminal cluster, called a cyme. I’ve counted up to as many as fifty buds in one cluster, but the number varies from a few to many on the individual plants. By definition, in a cyme, the terminal or top flower bud blooms first. In spiderwort, one or possibly two flowers will open in the early morning, fade, and be done blooming and closed by mid-day. Therefore, each individual flower blooms for just a few hours in one day. The following day, the next flower bud in line will bloom and close. This sequence continues until the last bud blooms. This delayed blossoming extends the plant’s flowering period.

With only a few fleeting hours to examine a flower, one must visit a prairie in the morning. Each inch-wide flower consists of three roundish blue to bluish-purple or pink petals. This year, I discovered one unusual white flower. One can’t help but notice the six bright, yellow stamens arranged in a ring around the flower’s center. Look more closely at the center. Hidden underneath, you will find tiny, delicate, soft, blue feathery hairs on each stamen’s stem. These fine, soft, unmatted hairs are botanically described as villose. I don’t know their function, but they were a surprise to discover. One can find beauty in the tiniest places!

Spiderwort flowers do not produce nectar to attract insects for pollination. Instead, they offer pollen. Female bees, especially bumblebees, become regular spiderwort visitors and do pollinate the flowers with a pollen reward. The fruit develops into a small papery round capsule.

Common spiderwort may be found throughout most of Wisconsin in wet meadows, prairies, and along roadsides, but less so in the north woods. Wisconsin has three spiderwort species. The other two species: prairie or western spiderwort (Tradescantia occidentalis) and long-bracted sticky spiderwort (Tradescantia bracteata) are rare in the state.

One question about spiderwort still puzzles me. Why is the plant called spiderwort? Is it because it looks like a spider? Imagine that the round flower cluster is the spider body, and that the leaves and bracts could be a jumble of spider legs, but this image is pure conjecture on my part.

I never tire of seeing spiderwort. With narrow, pointed leaves and bracts, its appearance is unique. Its fleeting sky blue flowers are blue jewels in a sea of green. Spiderwort seems to be in a hurry and waits for no one. Consequently, an early morning stroll in a prairie is a must to witness these beautiful blue flowers. But what a great way to begin the day!

The photo on my e-mail is a bee and ant on Ohio spiderwort by Robert Carlson.